US2197864A - Process of electrostatic separation - Google Patents

Process of electrostatic separation Download PDF

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Publication number
US2197864A
US2197864A US151950A US15195037A US2197864A US 2197864 A US2197864 A US 2197864A US 151950 A US151950 A US 151950A US 15195037 A US15195037 A US 15195037A US 2197864 A US2197864 A US 2197864A
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United States
Prior art keywords
cement
electrodes
group
minerals
separation
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Expired - Lifetime
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US151950A
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English (en)
Inventor
Herbert B Johnson
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RITTER PRODUCTS Corp
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RITTER PRODUCTS CORP
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Priority to US151950A priority Critical patent/US2197864A/en
Priority to FR839682D priority patent/FR839682A/fr
Priority to GB1402/40A priority patent/GB519817A/en
Priority to DER102741D priority patent/DE764281C/de
Application granted granted Critical
Publication of US2197864A publication Critical patent/US2197864A/en
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C7/00—Separating solids from solids by electrostatic effect
    • B03C7/02—Separators
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C7/00—Separating solids from solids by electrostatic effect
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B03—SEPARATION OF SOLID MATERIALS USING LIQUIDS OR USING PNEUMATIC TABLES OR JIGS; MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C—MAGNETIC OR ELECTROSTATIC SEPARATION OF SOLID MATERIALS FROM SOLID MATERIALS OR FLUIDS; SEPARATION BY HIGH-VOLTAGE ELECTRIC FIELDS
    • B03C7/00—Separating solids from solids by electrostatic effect
    • B03C7/02—Separators
    • B03C7/06—Separators with cylindrical material carriers
    • C—CHEMISTRY; METALLURGY
    • C04—CEMENTS; CONCRETE; ARTIFICIAL STONE; CERAMICS; REFRACTORIES
    • C04B—LIME, MAGNESIA; SLAG; CEMENTS; COMPOSITIONS THEREOF, e.g. MORTARS, CONCRETE OR LIKE BUILDING MATERIALS; ARTIFICIAL STONE; CERAMICS; REFRACTORIES; TREATMENT OF NATURAL STONE
    • C04B7/00—Hydraulic cements
    • C04B7/36—Manufacture of hydraulic cements in general
    • C04B7/38—Preparing or treating the raw materials individually or as batches, e.g. mixing with fuel

Definitions

  • This invention relates, generally, to the special application of improved electrostatic separation (a dry process) used for the separation, concentration and recombination of associated minerals found in rocks, shales, marls and the like and various by-products which are suitable for raw cement mixes used in the production of cement products and made to standard and special specifications and, in particular to the processing of the cement quarry rocks located in the Chester Valley and Lehigh Valley districts in the State of Pennsylvania.
  • electrostatic separation a dry process
  • Marketable cement is produced from low grade quarry rocks, shales, marls and the like, as well as from waste materials, such as blast furnace slag, boiler ash and the tailings or waste products from concentrating mills, which have previously been separated by mechanical means from 30 copper, zinc, iron, gold, silver and many other ores by well known methods of separation and concentration, such as air separators, wet tables and flotation, employing both wet and dry methods of concentration.
  • silica in the form of silicates, readily combines with the CaCOs minerals in burning or clinkering operations, while free silica (hard quartz) does not so readily combine.
  • the object of the invention is to provide a new processfor manufacturing cement that will be simple and eicient in operation and which may be readily and economically employed.
  • the principal object of the invention is to provide a dry process to meet the requirements of dry process cement plants.
  • the electrostatic principle of separation is the proper basic principle to apply for obtaining the lowest operation cost.
  • the electrostatic principle of separation eliminates the cost incident to the purchase of limestone and also the extra drying cost -required when the wet process is used.
  • the cement manufacturer with a yearly'prod'uction 0f 2,000,000 barrels of cement using the dry process disclosed herein will, therefore, receive a profit of approximately $100,000.00 yearly or a saving of this amount from which only the actual separating equipment cost and operation cost need be deducted.
  • Another object of the invention is to employ this new discovery in providing a high degree of iiexibility in the separating of the various mineral groups found in cement raw materials, principally the CaCOs group and the S102 group, so that different cement specifications can be readily met without requiring a long delay from the time that it is desired to alter the separation obtained.
  • an important object of the invention is to provide a process for manufacturing cement in which the quarry rock is processed in accordance with its varying chemical analysis and without particular regard to a nal product and in which different cement specifications can be met without requiring any change in the processing of the raw cement minerals.
  • Figures 1, 2, 3 and 44 illustrate diagrammatically the various separations that may be obtained /with the electrostatic eld acting in opposite directions;
  • Figures 5, 6, 7 and 8 illustrate, diagrammatically, the separating characteristics that may be obtained when either a plurality of electrostatic fields are employed acting oppositely in different separators or acting oppositely in the same separator;
  • FIGS 9, 10, 11, 12 and 13 show different flow sheets that may be employed in practicing the invention.
  • Electrodes X and Y are provided and they are arranged to be rotated in the directions indicated by the arrows i8 and I9.
  • the electrodes X and Y may form a part of an electrostatic separating machine such as that disclosed in the copending application of Herbert B. Johnson, Serial No. 128,097, filed February 27, 1937.
  • the electrodes X and Y are generally cylindrical in shape and are preferably relatively long, for example, from 6 to 8 feet long.
  • the electrodes X and Y maybe maintained at a high difference of uni-directional voltage by a suitable source of direct current such as the mechanical rectifier shown generallyI at 20.
  • the mechanical rectifier 20 may ⁇ be connected for energization to the high voltage winding 2
  • a reversing switch R is provided for reversing the connections between the primary winding 23 and the alternating current source 24.
  • the reversing switch R is operated to such position that the electrode X is maintained at a positive potential with respect to the electrode Y.
  • the electrode X may then be considered the positive electrode and' the electrode Y may be considered the negative electrode.
  • lUnderftheae conditions charging or electrostatic current iiows as indicated ⁇ by the arrow 25.
  • the cement minerals will be separated into two general groups which may be termed the CaCO: group, represented by-the reference characterl C and the SiO: group, represented by the reference character S.
  • the CaC group will be attracted tov the negative electrode Y while the SiO: group will be repelled therefrom to such an extent that the two groups may be separated by the divider 21.
  • CaCOa group and the SiO: group of 'minerals are important and constitute a major portion of the cement'minerals, they do not constitute all of the minerals that are present. Additional minerals may comprise an AlOs group, graphitic carbon, aluminum silicates and the like. It is then found that this latter general group of minerals is unaffected bythe reversal of the polarities of the electrodes X and Y.
  • group and associated minerals may be represented by the reference character A and this group is repelled further from the material carrying electrode Y than is ⁇ the CaCO: group.
  • 'I'he threeI groups may then be individually collected by means of dividers 29, 30 and 3
  • the CaCO: product is repelled from the positive electrodes Y and it is separted from the remainder by suitable dividers as shown. The balance of the material is then fed onto the next positive electrode and the separation is repeated, removing more and more-of the CaCO: product as the balance of the material passes between each successive pair of electrodes.
  • Product conveyors shown generally at 3
  • cement of this composition will have excellent strength characteristics which are considerably above standard specifications, although the cement has been produced from a raw material which was previously considered unsuitable for cement manufacture without being enriched in CaCO-s content by the addition of high grade limestone.
  • FIG 8 of the drawings another embodiment of the invention is illustrated in which two sets of oppositely energized electrodes are employed.
  • the rst four pairs of electrodes are so energized that the X electrodes are positive and the Y or material carrying electrodes are negative.
  • a cement product is then obtained in the product conveyor 33 and the balance of the material is then successively subjected to the next set of electrodes which are so energized that the X electrodes are negative and the Y or material carrying electrodes are positive.
  • This balance of the cement minerals is separated into rejects and middlings.
  • the former is received and conveyed 'away by the product conveyor 3
  • the concentrates obtained by this separation are Original Raw materock dust Cgerrtes rial mixture 74 pms) p (10o pms) Percent. Percent Percent Loss 35. 50
  • the separating arrangement shown in Figure 7 may be employed and, as shown in Table 5, for the given crude rock analysis the AlzO's in the concentrates is 4.10 per cent.
  • the separating arrangement shown in Figure 8 is employed a smaller A1203 content of the concentrates is obtained.
  • the A1203 content of the concentrates is 2.55 per cent.
  • each set may be individually energized from a suitable source of uni-directional voltage with suitable reversing switches for reversing the polarities of the electrodes as desired.
  • a suitable source of uni-directional voltage with suitable reversing switches for reversing the polarities of the electrodes as desired.
  • the electrostatic separation is so arranged as to treat the entire rawl material after it has been suitably reduced in size by crushing and grinding it.
  • the finely divided raw material is separated into rejects, middlings and concentrates.
  • the middlings are returned to be reground and reprocessed.
  • The'rejects may be discarded if desired.
  • the concentrates are further processed in accordance with standard cement mill practice.
  • a final grinding and mixing step is introduced before the product is sent to the kiln bins. This additional step not only reduces the cement product to final size but, by virtue of the grinding process, an intimate mixture is obtained. This step is believed to be new in cement mill practice.
  • a final wet grinding step may be incorporated as illustrated, to thoroughly mix the products involved as well as to reduce them to the desired size.
  • the material passes through the thickener and then to the various storage blending tanks as desired.
  • the material from the various tanks may be withdrawn onto the kiln feed conveyor and conveyed to the kiln bins in accordance with the standard cement practice..
  • the concentrates from the electrostatic separation and the dust are suitably combined to form a product that may be combined with other products to meet different cement specications.
  • the rejects are further treated by grinding and roasting them and then magneticallyseparating them to remove the Fea04 and A1203 concentrates.
  • 'I'he balance of the rejects or middlings are conveyed to suitable storage bins.
  • 'I'hese three products, i. e., concentrates and middlings from'the rejects and combined concentrates and dust may be suitably combined and conveyed by the kiln feed conveyor to a point where the final grinding and mixing may be completed. As indicated this final grinding and mixing step reduces the minerals to the desired size and at the same time intimately mixes them.
  • this invention provides a highly flexible dry processv for manufacturing cement.
  • the recombination steps are, for al1 practical purposes, disassociated from the concentrating steps.
  • the run-of-mine rock may be regularly processed and the dust and concentrated CaCOs, SiO2 and A1203 products may be separately stored. Since the quantity and analysis of each product is known, it is a routine 'matter for the cement chemist to make the necessary recombinations to meet different cement specifications.
  • the cost of operation of many dry process plants is reduced and at the same time they are capable of more easily meeting different cement specifications.
  • many plants that have been abandoned because of high cost operation can be reopened and lower grade deposits of cement rock made available.
  • cement raw material between a pair of continuously' rotating electrodes maintained atV a high difference of uni-directional voltage and in close proximity to one vof them, separating the finely divided cement raw material into a plurality of discrete portions by the selectiveactiotn of the electrostatic field between the electrodes, and individually collecting the separated portions.
  • the steps which comprise: passing finely divided cement raw material between a pair of continuously rotating electrodes maintained at-a high difference of uni-directional voltage in close proximity to the negative electrode, separating the finely divided cement raw material into a plurality of discrete portions by the selective action of the electrostatic field between the ielectrodes, and individually collecting the separated portions.
  • the steps which comprise: passing finely divided cement raw material between a pair of continuously rotating electrodes maintained at a high difier- ⁇ ence of uni-directional voltage in close proximity to the positive electrode, separating the finely divided cement raw material into a plurality of discrete portions by the selective ac4 I tion of the electrostatic field between the elec- "to the negative electrodes, separating the finely 'divided cement raw material intov saidgroups l"with the S102 group being repelled from each trodes, and individually collecting the separa portions.
  • the steps which comprise: passing the finely divided cement raw material between a3 pair of lcontinuously rotating electrodes main- ,tained at .a high difference of uni-directional voltage and in close proximity to the positive electrode, separating the finely divided cement raw material into said groups with the CaCO: group being repelled from the positive electrode further than the SiO: group, and individually collecting the separatedl groups.
  • the steps which comprise: passing the finely divided cement raw material between a pair of continuously rotating electrodes maintained at a high difference of uni-directional voltage and in close proximity to the negative electrode, separating the finely divided cement raw ,material into said groups with the SiOz group being repelled from the negative electrode further than the CaCO: group, and individually colseparated groups.
  • the steps whiclr comprise: successively' and hindividually collecting the separated groups.
  • steps which comprise: successively passing th'e iinely divided cement raw material between a plurality of pairs of continuously rotating electrodes maintained at a high difference of uni-directional voltage and in close proximity negative electrode further than the CaCO: group, and individually collecting the separated groups.
  • the steps which comprise: successively passing finely divided cement raw material between a plurality of pairs of continuously rotating electrodes maintained at a high dierence of unidirectional voltage and in close proximity to the l negative electrodes, separating the finely divided cement raw material into a plurality ofv discrete portions, removing at least one of the separated portions, successively passing the balance of the finely divided cement raw material between a plurality of pairs vof continuously rotating electrodes maintained at a high difference of unidirectional voltage and in close proximity to the I positive electrodes, separating the balance of the finely divided cement raw material into a plurality of discrete portions, and individually collecting the last named separated portions.
  • the steps which comprise: lsuccessively passing finely divided cement raw material between a plurality of pairs of continuously rotating electrodes maintained at a high difference of unidirectional voltage and in close proximity to the positive electrodes, separating the finely dividf ed cement raw material into a plurality of discrete portions, removing at least one of the separated portions, successively passing the balance of the finely divided cement raw material between a plurality. of pairs of continuously rotating electrodes maintained at a high difference of unidirectional voltage and in close proximity to the negative electrodes, separating the balance ofthe finely divided cement raw material into a plurality of discrete portions, and individually collecting the last named separated portions.
  • the steps which comprise: successively passing the iinely divided cement raw4 material between a plurality of pairs of continuously rotating electrodes maintained at a high difference 30 of uni-directional voltage and in close proximity to the positive electrodes, separating the iinely divided cement raw material into said groups with the CaCO: group being repelled from each positive electrodeY further than the S102 group,
  • the method of separating a mixture of 5 finely divided material comprising two groups each susceptible to opposite polarities into said groups which comprises: passing the mixture.
  • the method of separating a mixture of nely divided material comprising two groups each susceptible to opposite polarities into saidv groups which comprises: passing the mixture between a pair of continuously rotating electrodes individually collecting the separated groups.
  • the method of separating a mixture of nely divided material comprising two groups each susceptible to opposite polarities and another group susceptible to either polarity into said groups which comprises: passing the mixture between a pair of continuously rotating electrodes maintained at a relatively high diierence of uni-directional voltage and in close proximity to one of them to separate the same into said groups, controlling the relative positions of said two groups by the relative polarities of said electrodes while the position of said other group Iremains substantially unaffected, and individually collecting theseparated groups.
  • the steps which comprise: passing the finely divided cement raw material between a pair of electrodes maintained at a high difierence of uni-directional voltage and 'in close proximityto one of them to separate the same into said groups, controlling the relative positions of said groups by the relative polarities of said electrodes, and individually collecting the separated groups.
  • the steps which comprise: feeding iinely divided cement raw material between a pair of electrodes maintained at a high diiierence of unidirectional voltage and in close proximity to one I of them to separate the same into a plurality of discrete portions, removing at least one of the separated portions, feeding the balance of the iinely divided cement raw material between a pair of electrodes maintained at a high diilerence of uni-directional voltage and in close proximity to the electrode having a polarity opposite to the polarity of the electrode in close proximity to which the material is first fed to separate the same into a plurality of discrete portions, and individually collecting the last named separated portions.

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  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
  • Materials Engineering (AREA)
  • Structural Engineering (AREA)
  • Organic Chemistry (AREA)
  • Electrostatic Separation (AREA)
  • Sheets, Magazines, And Separation Thereof (AREA)
US151950A 1937-07-03 1937-07-03 Process of electrostatic separation Expired - Lifetime US2197864A (en)

Priority Applications (4)

Application Number Priority Date Filing Date Title
US151950A US2197864A (en) 1937-07-03 1937-07-03 Process of electrostatic separation
FR839682D FR839682A (fr) 1937-07-03 1938-06-23 Procédé de fabrication de ciment
GB1402/40A GB519817A (en) 1937-07-03 1938-07-01 Improvements in and relating to electrostatic separators
DER102741D DE764281C (de) 1937-07-03 1938-07-02 Einrichtung zum elektrostatischen Scheiden von Rohgestein fuer die Zementherstellung und von sonstigen Stoffen

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DE (1) DE764281C (de)
FR (1) FR839682A (de)
GB (1) GB519817A (de)

Cited By (15)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2559076A (en) * 1945-10-11 1951-07-03 Quaker Oats Co Method of cleaning coal
US2813626A (en) * 1953-11-24 1957-11-19 Quaker Oats Co Method for separating asbestos from its ores
US2825078A (en) * 1953-04-07 1958-03-04 Western Electric Co Electrostatic apparatus for separating articles
US2839189A (en) * 1954-02-01 1958-06-17 Quaker Oats Co Electrostatic separation method
US2848727A (en) * 1953-04-07 1958-08-26 Western Electric Co Apparatus for separating articles
US3114482A (en) * 1962-04-30 1963-12-17 Ralph H Dunaway Apparatus for dispensing dry powdered material
DE1159362B (de) * 1959-09-11 1963-12-19 Foster Fraas Elektrostatischer Scheider
US3184901A (en) * 1959-12-08 1965-05-25 Lab For Electronics Inc Gaseous concentration and separation apparatus
US4341744A (en) * 1979-01-22 1982-07-27 Stauffer Chemical Company Soda ash production
EP1334772A1 (de) * 2000-09-04 2003-08-13 Hitachi Zosen Corporation Vorrichtung zur trennung von kunststoffchips
US20170198394A1 (en) * 2016-01-13 2017-07-13 Product Innovation and Engineering L.L.C. Electrostatic powder feeder
US20180243769A1 (en) * 2017-02-24 2018-08-30 Powder Motion Labs, LLC Electrostatic powder feeder
US10800615B2 (en) 2018-03-16 2020-10-13 Power Motion Labs, LLC Electrostatic conveyor-wheel powder feeder
US11772164B2 (en) 2020-03-18 2023-10-03 Powder Motion Labs, LLC Powder bed recoater
US11872754B2 (en) 2020-03-18 2024-01-16 Powder Motion Labs, LLC Recoater using alternating current to planarize top surface of powder bed

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE29519673U1 (de) * 1995-12-12 1996-02-01 Lorch, Andreas, Dipl.-Ing., 49419 Wagenfeld Hochspannungs-Elektrostatischer Kunststoffabscheider (Separator)

Family Cites Families (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US653343A (en) * 1899-12-02 1900-07-10 Theodore J Mayer Electrostatic separation.
DE162747C (de) * 1903-12-28
FR441053A (fr) * 1912-03-07 1912-07-29 Auguste Mesmin Frederic Blanch Appareil séparateur électrostatique pour le classement des matières hétérogènes, notamment des minerais métalliques ou autres, soufre, phosphates de chaux, etc.
AT66441B (de) * 1912-03-29 1914-08-25 Auguste Mesmin Frede Blanchard Elektrostatischer Separator.
FR486891A (fr) * 1917-09-20 1918-05-15 Huff Electrostatic Separator C Méthode et appareil pour la séparation électrostatique
US1663863A (en) * 1924-11-28 1928-03-27 Royster Percy Hoke Process for separating various constituents from mixed materials and apparatus for accomplishing said separation
DE633094C (de) * 1934-03-10 1936-07-18 Metallgesellschaft Akt Ges Elektrostatischer Scheider zur Trennung elektrisch sich verschieden verhaltender Teilchen eines Gemenges
DE633095C (de) * 1935-01-17 1936-07-18 Metallgesellschaft Akt Ges Verfahren und Scheider zur elektrostatischen Scheidung

Cited By (19)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2559076A (en) * 1945-10-11 1951-07-03 Quaker Oats Co Method of cleaning coal
US2825078A (en) * 1953-04-07 1958-03-04 Western Electric Co Electrostatic apparatus for separating articles
US2848727A (en) * 1953-04-07 1958-08-26 Western Electric Co Apparatus for separating articles
US2813626A (en) * 1953-11-24 1957-11-19 Quaker Oats Co Method for separating asbestos from its ores
US2839189A (en) * 1954-02-01 1958-06-17 Quaker Oats Co Electrostatic separation method
DE1159362B (de) * 1959-09-11 1963-12-19 Foster Fraas Elektrostatischer Scheider
US3184901A (en) * 1959-12-08 1965-05-25 Lab For Electronics Inc Gaseous concentration and separation apparatus
US3114482A (en) * 1962-04-30 1963-12-17 Ralph H Dunaway Apparatus for dispensing dry powdered material
US4341744A (en) * 1979-01-22 1982-07-27 Stauffer Chemical Company Soda ash production
EP1334772A1 (de) * 2000-09-04 2003-08-13 Hitachi Zosen Corporation Vorrichtung zur trennung von kunststoffchips
EP1334772A4 (de) * 2000-09-04 2010-03-03 Hitachi Shipbuilding Eng Co Vorrichtung zur trennung von kunststoffchips
US20170198394A1 (en) * 2016-01-13 2017-07-13 Product Innovation and Engineering L.L.C. Electrostatic powder feeder
US10035219B2 (en) * 2016-01-13 2018-07-31 Product Innovation and Engineering L.L.C. Electrostatic powder feeder
US20180243769A1 (en) * 2017-02-24 2018-08-30 Powder Motion Labs, LLC Electrostatic powder feeder
US10213797B2 (en) * 2017-02-24 2019-02-26 Powder Motion Labs, LLC Electrostatic powder feeder
US10226780B2 (en) * 2017-02-24 2019-03-12 Powder Motion Labs, LLC Electrostatic powder feeder with vibratory assist
US10800615B2 (en) 2018-03-16 2020-10-13 Power Motion Labs, LLC Electrostatic conveyor-wheel powder feeder
US11772164B2 (en) 2020-03-18 2023-10-03 Powder Motion Labs, LLC Powder bed recoater
US11872754B2 (en) 2020-03-18 2024-01-16 Powder Motion Labs, LLC Recoater using alternating current to planarize top surface of powder bed

Also Published As

Publication number Publication date
DE764281C (de) 1951-08-23
FR839682A (fr) 1939-04-07
GB519817A (en) 1940-04-05

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